A downhole environment such as, for example, an oil or gas well in an oilfield or undersea environment, a gas sequestration well, a geothermal borehole, or other such environment, may expose equipment used downhole, such as packers, blow out preventers, drilling motor, drilling bit, and the like, to conditions which may affect the integrity or performance of the element and tools.
Where the article is an element having a rubber or plastic part or coating, downhole conditions may cause, for example, swelling by uptake of hydrocarbon oil, water or brine, or other materials found in such environments, and which can thereby weaken the structural integrity of the element or cause the element to have poor dimensional stability, resulting in difficulty in placing, activating, or removing the element. Likewise, where the element includes metallic components, these components may be exposed to harsh, corrosive conditions due to the presence of materials such as hydrogen sulfide and brine, which may be found in some downhole environments.
Protective coatings, and improved methods of forming protective coatings, are therefore desirable for use with such downhole elements, particularly coatings having improved barrier properties to resist exposure to a variety of different environmental conditions and materials found in downhole environments.